solar collectors can be built from aluminum flashing for foundations easily.

aluminum can solar collectors can be made easily too even without a glass top for non winter applications, have thought about using an old car before too. great for hot water / air in summer winter depending on the build.

solar waterer system for cattle

https://www.ebay.ca/itm/401436481978 took a month to ship, eventually did come but i was unable to leave feedback for it on ebay. puts out about 3.5v and 0.6 amps – 2 watts on a overcast day not sure it would see a full 10 watts of power unless a concentrator was used. (if you get one of these wash it off good(mostly the sides of it where the plastic layers meet), not sure if it was something i did but i had chemical taste in my mouth afterwards)